Rotor Tip Desensitisation
The present doctoral project concerns the reduction of sensitivity of the rotor tip in axial compressors. The tip of the rotor is known to be prone to secondary flow phenomena. The phenomenon with the biggest impact is Tip Leakage Flow (TLF), which is caused due to the pressure difference between the suction and pressure sides of the rotor blade. The interaction of this flow with the boundary layer on the casing leads the flow to curl up into a vortex, more specifically the Tip Leakage Vortex (TLV). These flow phenomena are the source of high instabilities that reduce the surge margin and increase the danger of stall. The objective of this project is to reduce the impact of the Tip Leakage Flow and increase the surge margin. Many ways of achieving this have been investigated in the past, mostly focusing on the casing of the compressor. However, these methods cause a reduction of the efficiency. As a result, this work aims to develop new methods of limiting the sensitivity of the rotor tip, with a decreased impact on the compressor efficiency. Various geometrical modifications will be designed and applied on the rotor and tested numerically, in order to investigate their contribution to facing this secondary flow phenomenon.
